Topdressing time frame

[DBM]

I'm giving my first estimate on seeding for a new customer of mine. I'd like to topdress but unsure of how long it will take me. Backyard is 2000 square feet and I'd have to wheelbarrow it down a 50 foot sidewalk first. Front yard is 1500 square feet.
How long would it take you to do this small property and how would you go about it?

Thanks
Doug